Solvent extraction equipment



April 24, 1956 L. l.. BURGER 2,743,170

' soLvENT EXTRACTION EQUIPMENT Filednems, 1952 HEATER INVENTOR. y Ze/alza l .3dr er United States Patent SOLVENT EXTRACTION EQUIPMENT Leland L. Burger, Richland, Wash., assignor to the United States of America as represented by the United States Atomic Energy Commission Application December 9, 1952, Serial No. 325,003

1 Claim. (Cl. 23--270.5)

This invention relates to the removal of materials, such as metal values or impurities, from a liquid by means of another liquid brought into intimate contact with the first liquid and then separated therefrom. More specifically the invention relates to moving such liquids in opposite direct-ion to one another and applying a pulse thereto to bring about intimate contact between them.

An object of .the .present invention is to provide an improvement in a liquid-extraction system involving moving two liquids in opposite directions or with counter-current l'low in intimate contact with one another brought about by pulses. With the present invention the pulses are applied to the liquids in a special way that is favorable to repeated intimate contact and separation of the liquids lwith and from one another, which result in a more eilic-ient removal .of material from the one liquid.

Other objects will become apparent from the specification and drawing.

In the drawing a pulse column comprises a vertical cylinder 11 and a plurality of perforated plates 12 spaced lengthwise of the cylinder 11. The plates 12 preferably `take the form of one of the embodiments disclosed in the Burns and Johnson patent, 2,662,001, issued December 8, v1953. Thus, each plate may comprise a pair of discs of different materials, one of which wets one `liquid `fed to the pulse column and the other `of which wets the A other liquid, for example, .a stainless steel disc and lluorothene disc. Alternatively, each plate may comprise one disc, vfor example, of stainless steel, and a plurality of short tubular parts, for example of `lluorothene, mounted in countersunk Vperforations in the disc.

The cylinder 11 has enlarged ends 13, on each of which there is a liang'e 14 which is bonded to. the end 13 or formed integral therewith. A closure plate 15 rests against each ilange 14 and is secured thereto in sealing relation by suitable means such as a collar 16, mounted on the cylinder end 13 beyond the flange 14, and bolts 17, passing through the collar 16 and the closure plate 15. A rod 18, which mounts the perforated plates 12, has its ends connected in the closure plates 15. The rod 18 comprises a plurality of short sleeves 19 which extend between the plates 12 so as to maintain them in spaced relation, two longer sleeves 19a which abut and extend beyond the end perforated vplates 12, a threaded member 20 which extends through the sleeves 19 and 19a and the perforated plates 12, and nuts 21 which are threaded on the member 20 so as to engage the ends of the sleeve 19a. By adjustment of the nuts 21 valong the member 20, the sleeves 19 and 19a vare adjusted lengthwise. of the member 20, and this accomplishes adjustment of the perforated plates 12 lengthwise of the cylinder 11.

The top closure plate 15 receives in tight connection a top inlet line 22, a topv outlet line 23, and a top bleeder line 24. VThe top inlet line 22 extends an appreciable distance beyond the top closure plate 15 and into the enlarged top end 13 of the cylinder 11. The. vtop bleeder line 24 extends a smaller distance ,beyond the top closure plate 15 and vintothe enlarged top cylinder end 13. The

2,743,170 Patented Apr. 24, 1956 "ice top outlet line 23 terminates above the top inlet line 22 and the top bleeder line 24 and may extend only just through the top closure plate 15 as shown in the drawing. The lines 22, 23, and 24 are provided, respectively, with valves 25, 26, and 27, which may take the form of solenoid valves, because they are to open and close quickly and should when open have passages yolf appreciable size. The top bleeder line 24 is also provided with a manual bleeder valve 28 between the valve 27 andthe top closure plate 15. A heater 29 is associated with the top inlet line 22 between the valve 25 and the top closure plate 15. The heater may actually surround a portion of the top inlet line.

The top inlet line 22 leads to apressure tank 30 which is connected by a line 31 with a pump 32. A line 33 connects the pump with a storage tank 34 for relatively heavy liquid. A by-pass line 35 is connected to the lines 31 and 33 around the pump 32 and has a valve 36. The pressure tank 30 may have a suitable air ballast to provide a steady predetermined pressure of liquid from the heavy-liquid tank in the line 22 at the side of the valve 25 toward the pressure tank. The `by-pass line 35 vand the valve 36 are adapted to keep the pump 32 `operating at a constant pressure. The topv bleeder line 24 leads to the heavy-liquid tank.

The bottom closure plate 15 receives in tight connections a bottom inletk line 37, a bottom outlet line 38, and a bottom bleeder line 39. The bottom inlet line 37 extends an appreciable distance beyond the bottom closure plate 15 and into the enlarged bottom cylinder end 13. The bottom bleeder line 39 extends a smaller distance beyond the bottom closure plate 15 and into the enlarged bottom cylinder end '13. The bottom outlet line 38 terminates below the lines 37 and 39 and may extend only just through the bottom closure plate 15 as shown inthe drawing. The lines 37, 38, and 39 are provided, respectively, with valves 40, 41, and 42 which are similar in action and construction to valves 25, 26, and 27. A heater 43 is associated with the vbottom inlet line 37 'between the valvet40 and the bottom closure plate 15. The heater may actually surround a portion of the bottom inlet line. A manual bleeder valve 44 is provided in the bottom bleeder line 39 between the valve 41 and the bottom closure plate 15.

The bottom inlet line 37 leads to a pressure tank 45, which is connected by a line 46 with a pump 47. A line 48 connects the pump with a storage tank 49 for relatively light liquid. A by-pass line 50 is connected to the lines 46 and 48 around the pump 47 and .has a valve 51. The pressure tank 45 yis similar to the pressure ltank 30 and kis adapted to provide a steady predetermined pressure of liquid from the light-liquid tank in the line 37 at the side of the valve 40' toward the pressure tank 45. The bypass line 50 and the valve 51 are adapted to keep kthe pump -47 operating at a constant pressure. The bottom bleed line 39 leads to the light-liquid tank. l

A water jacket 52 surrounds the cylinder 11 and cooperates with the heaters 29 and 43 to provide for operation of the apparatus of the present invention at elevated temperatures. The jacket has suitable inlet and outlet tubes 53. l i The drawing provides a diagrammatic representation of how the valves 25, 26,27, 40, 41, and 42 are connected for operation. A timer 54, which may be electronic, is connected with all the valves. A lead 55 runs from the valve 25 to one end ofthe timer. The valves 41 and 42 are shown connected to the same end of the timer, and thus it is indicated that valves 41 and 42 may operate simultaneously with the valve 25. Leads 56 and 57 from the valves 41 and 42 have a connectionSS, which assures simultaneous actuation of valves 41 and 42. The connection 58 is tied to the timer 54 by a lead S9, a delaying control 60, a lead 61, and a three-way control 62. The delaying control may be employed to cause the valves 41 and 42 to be opened and closed subsequently to or simultaneously with the valve 25, as may be desired. The three-way control 62 permits the valves 41 and 42 to be kept continuously open, to be kept continuously closed, or to be operated in the timed relation to the valve 25 for which the control 60 is set.

A lead 63 runs from the valve 40 to the end of the timer 54 away from the end at which the valves 2S, 41, and 42 are connected, so as to indicate that the operation of valve 40 is completely separate from that of valves 25, 41, and 42. The valves 26 and 27 are connected to the same end of the timer 54 as the valve 40, and thus it is indicated that the operation of the valves 26 and 27 may be tied to that of the valve 40. Leads 64 and 65 from the valves 26 and 27 have a connection 66, which assures simultaneous operation of these valves. The connection 66 is tied to the timer 54 by a lead 67, a delaying4 control 68, a lead 69, and a three-way control 70. The delaying control may be employed to cause the valves 26 and 27 to be opened and closed subsequently to or simultaneously with the valve 40, as may be desired. The three-Way control 70 permits the valves 26 and 27 to be kept continuously open, to be kept continuously closed, or to be operated in the timed relation to the valve 40 for which the control 68 may be set.

lt is contemplated that with the apparatus of the present invention a relatively heavy liquid will go from the tank 34 through the top inlet 22 into the cylinder 11, downwardly through the cylinder, and out the bottom outlet line 38; that a relatively light liquid will go from the tank 49 throughthe bottom inlet line 37 into the cylinder 11, upwardly through the cylinder, and out the top outlet line 23; and that the liquids will become mixed as they pass through one another on their way along the cylinder and become separated before leaving the cylinder. The purpose of this mixing and separation of the fluids may be to transfer some impurity or ingredient contained in the one liquid to the other liquid. The heavy liquid may be an aqueous liquid, for example, aqueous solutions of metal salts such as aqueous cerium (IV) nitrate solution, extractable by organic solvents. The light liquid may be a water-immiscible organic solvent such as tributyl phosphate, dissolved in a hydrocarn bon base such as a kerosene type of petroleum fraction, which is employed to make light liquid light in contrast with the heavy aqueous liquid. Thus the heavy liquid will flow down through the cylinder 11, and the light liquid will ow up through the cylinder. If the heavy liquid admitted to the top of the cylinder is an aqueous liquid of the type specified, and the light liquid admitted to the bottom of the cylinder is an organic solvent of the type specified, then the stainless steel portion of each perforated plate will be at the top side thereof, and the tluorothene portion will be at the bottom side, since stainless steel is wetted by the aqueous liquid, and fluorothene by the organic solvent.

The signicant feature of the present invention is that the top inlet valve 25 is opened and closed simultaneously with or slightly before the bottom outlet valve 41, that the bottom inlet valve 40 is opened and closed simultaneously with or slightly before the top outlet valve 26, and that between the aforementioned alternating or staggered periods of simultaneous or nearly simultaneous operation of the above valves, there are two periods in which all these valves are closed, one all-closed period occurring after the open period for one set of valves, and the other allclosed period occurring after the period for the other set of valves. A concomitant inventive feature is that the top bleeder valve 27 is opened and closed simultaneously with the top outlet valve 26 and that the bottom bleeder valve 42 is opened and closed simultaneously with the bottom outlet valve 41.

The elect of opening either inlet valve is to provide a pulse to the mixture of liquids in the cylinder 11 by the admission of a certain quantity of the liquid controlled by the particular inlet at the pressure determined by the associated pressure tank 30 or 45 and by-pass valve 36 or 51. The pulse applied is appreciable, because the inlet valve is to be opened suddenly a substantial amount to provide a passage through the valve of considerable area. This type of operation is characteristic of a solenoid valve, which thus may be the form of valve employed.

lu operation the cylinder 11 may first be partially lled with heavy liquid pumped from the tank 34 through the top inlet valve 25 which is kept open or is intermittently opened, while the bottom outlet valve 41 and bottom bleeder valve 42 are kept continuously shut. Manual valve 44 is kept open. The cylinder 11 may be filled with heavy liquid to about the lower portion of the upper enlarged end 13 of the cylinder. Now admission of heavy liquid to the cylinder 11 is stopped and pulsing of the light liquid from the tank 49 into the cylinder 11 is begun by periodic opening and closing of the bottom inlet valve 40, while the top outlet valve 26 is held open and the top bleeder line 24 is kept closed by closing of the manual bleeder valve 28. The action of the perforated plates 12 will be to create two interfaces between the liquids in the cylinder 11, one in the lower end 13, and the other in the upper end 13. The interface in the lower end should be somewhat lower than the end of the lower bleeder line 39, and the interface in the upper end should be somewhat higher than the end of the upper bleeder line 24.

Now the apparatus of the present invention is ready for complete operation, in which the top inlet valve 25 operates conjointly with the bottom outlet valve 41 and the bottom bleeder valve 42 and the bottom inlet valve 40 operates conjointly with the top outlet valve 26 and the top bleeder valve 27 at periods spaced in both direc tions in time from the periods of operation of the valves 25, 41, and 42. The manual bleeder valves 28 and 44 are, of course, kept continuously open now. When the top inlet valve 25 opens, and the bottom outlet valve 41 and the bottom bleeder valve 42 also open simultaneously therewith or somewhat subsequently thereto, a pulse of heavy liquid athigh pressure is admitted at the top of the cylinder ythrough the top inlet valve 25, and a corresponding amount of heavy liquid is removed from the bottom of the cylinder mostly through the bottom outlet line 38 so that the amount of heavy liquid in the cylinder is kept relatively constant. When the bottom inlet valve 40 opens, and the top outlet valve 26 and the top bleeder valve 27 also open simultaneously therewith or somewhat subsequently thereto, a pulse of light liquid at high pressure is admitted at the bottom of the cylinder 11, and a corresponding amount of light liquid is removed from the top of the cylinder mostly through the top outlet line 23, so that the amount of light liquid in the cylinder is kept relatively constant. The alternate pulses spaced from one another of heavy liquid and light liquid that nd their way through the perforated plates 12 down through the cylinder and up through the cylinder, respectively, provide the proper sort of contact of the liquids with one another for transferring the impurities, etc. from the one liquid to the other. It is important that between the pulses there are periods in which all the intermittently opening valves are closed and thus there areno pulses, Thus there are alternate periods in which the liquids alternately become dispersed and settle out. This condition makes for an etlicient transfer of material from one liquid to the other.

The bleeder lines 24 and 39 and their valves 27, 28, '42, and 44 control the levels of the two interfaces at the ends 13 of the cylinder 11, so that the top interface cannot rise to the top closure plate 15 and cause heavy liquid to go out through the top outlet line 23 and the bottom interface cannot descend to the bottom closure plate 15 and cause the light liquid to go out through the bottom outlet line 38.y Thus each time a particular outlet valve 26 or 41 is opened to let one liquid out ofthe cylinder, the

sequently to the inlet valve 40 or 25, rather than simultaneously thereto, and this will be accomplished by use of the delaying control 68 or 60.

While one embodiment of the instant invention has been presented, various modications within thescope of the invention will be apparent to those skilled in the art. The invention is not limited by these embodiments but only by the claim which follows.

What is claimed is:

An apparatus for intimately contacting and separating substantially immiscible uids of diiferent specific gravities comprising a column, a plurality of perforated plates horizontally disposed at vspaced intervals within the column, a rst inlet line for light fluid communicating with the bottom of the column, a second inlet line for heavy uid communicating with the top of the column, a irst outlet line for light uid communicating with the column at a point above the point of introduction of the heavy iluid, a second outlet line for heavy fluid communicating with the column at a point below the point of introduction of the light luid, a first bleed outlet line communicaing with the column between the points of introduction of heavy iluid and of withdrawal of light fluid, a second bleed outlet line communicating with the column between the points of introduction of light fluid and of withdrawal of heavy uid, pumps for introducing heavy and light lluids into the column through the rst and second inlet lines, valves in each of said inlet and outlet lines, timing means for controlling said Valves, said timing means being adapted and arranged to automatically and alternately (l) open the valves in the rst inlet line, Iirst outlet line, and iirst bleed outlet line and close the valves in the -second inlet line, second outlet line, and second bleed outlet line and (2) open the valves in the second inlet line, second outlet line,vand second bleed outlet line and close the valves in the first inlet line, first outlet line, and irst bleed outlet line, and additional valves in said bleed outlet lines for controlling the flow therethrough by which construction heavy uid may be bled through the rst bleed outlet line to prevent heavy fluid from passing out the light uid outlet and light fluid may be bled through the second bleed outline line to prevent light fluid from passing out the heavy lluid outlet.

References Cited inthe file of this patent UNlTED STATES PATENTS 2,011,186 Van Dijck Aug. 13, 1935 2,474,007 Maycock June 21, 1949 2,480,471 Ittner Aug. 30, 1949 2,609,277 McNamara Sept. 2, 1952 2,629,654 Olney Feb. 24, 1953 

